Automatic stop cock valve

ABSTRACT

A flow control device includes a fitting having three portals. Two of the portals are input portals and one of the portals is an exit portal. Located in one of the input portals is a normally closed back flow prevention valve. The normally closed back flow prevention valve prevents back flow of fluid through the fitting when the fluids flowing through the fitting are changed.

FIELD

The present invention pertains to a fluid flow fitting; more particularly the present invention pertains to a fluid flow fitting having a back flow prevention valve included therein.

BACKGROUND

In the process of performing medical procedures involving the use of different fluids, such a vitreoretinal surgery, it is not uncommon to use different gases and liquids. For example in vitreoretinal surgery, the need may arise to exchange fluid from the interior of the eye and replace it with air.

In prior art vitreoretinal surgical systems, the exchange of fluid from the interior of the eye with air is typically performed by manually changing the position of a stop cock valve. In vitreoretinal surgery, the manual switching of a stop cock valve stops the flow of a primary fluid such as a surgical infusion solution (e.g. BSS PLUS® intraocular irrigating solution available from Alcon Laboratories, Inc. of Fort Worth, Tex.) and starts the flow of an alternate fluid such as air. For the surgeon performing the vitreoretinal surgery—when time comes to stop the flow of surgical infusion solution and begin the flow of air—it has been necessary for the surgeon to verbally request that his assistant, fellow, scrub nurse or scrub tech in the operating room change the position of the stop cock valve. This technique can delay surgical procedures and lead to errors. If the stop cock valve is inadvertently turned to a non-functional position, the flow of fluid to the eye will be interrupted and the eye may go soft, thus further complicating an already delicate surgical procedure. Alternatively, improper manipulation of the stop cock valve introduces the possibility of unwanted back flow of the fluids.

Accordingly there remains a need in the art for a system and method that will provide a vitreoretinal surgeon direct control to shift between the flow of surgical infusion solution and the flow of air, without the potential for back flow, and without the need for assistance. Further, there remains a need in the art for a system and method that will eliminate the potential for the complication of a soft eye during surgery by a valve being turned to a non-functional position.

SUMMARY

There is provided by the disclosed invention a system and method which enables a vitreoretinal surgeon to switch between surgical infusion solution and air without the need for assistance and without creating the potential for a soft eye by having the flow of fluids interrupted.

According to the disclosed invention, the sources of surgical infusion solution and air are connected to a fitting having three portals. Two of the portals are input portals; one input portal for a fluid such as surgical infusion solution and the other input portal for fluid such as air. The third portal is an exit or outflow portal.

In one of the input portals is located a normally closed back flow prevention valve. Accordingly, when the infusion solution pressure is decreased to less than the air pressure and/or the air pressure is increased higher than the infusion solution pressure, the flow through the device switches from infusion solution to air. The air pressure opens the normally closed valve, allowing the flow of air to supplant the flow of the infusion solution. Because of the back flow prevention valve there will be no back flow of surgical infusion solution into the source of air.

An alternative embodiment may utilize the above-described fitting with a first means for stopping the flow of the infusion fluid and a second means for stopping the flow of the air or gas. In this embodiment, the backflow prevention valve is not required.

BRIEF DESCRIPTION OF THE DRAWING FIGURES

A still better understanding of the automatic stop cock valve of the present invention may be had by reference to the drawing figures described below when read in conjunction with the Description of the Embodiments which follows.

FIG. 1 is a schematic diagram of a prior art fluid flow system using a stop cock valve that is associated with a vitreoretinal surgery system;

FIG. 2 is a schematic diagram of a fluid flow system using the automatic stop cock valve of the present invention;

FIG. 3 is a side elevational view in partial section of the automatic stop cock valve system of the present invention incorporating a duck bill valve;

FIG. 4 is a side elevational view in partial section of a first alternate embodiment incorporating a normally closed flapper type valve;

FIG. 5 is a side elevational view in partial second of a second alternate embodiment incorporating a normally closed umbrella valve;

FIG. 6 is a side elevational view in partial section of a third alternate embodiment incorporating a normally closed ball valve;

FIG. 7 is a side elevational view in partial section of a fourth alternate embodiment incorporating a normally closed poppet valve;

FIG. 8 is a side elevational view in partial section of an embodiment similar to that of FIG. 6 but showing the use of a Y-shaped housing to enclose the normally closed ball valve; and

FIG. 9 is a side elevational view in partial section of an embodiment similar to that of FIG. 8 but schematically showing a first means for stopping the flow of a first fluid and a second means for stopping the flow of a second fluid.

DESCRIPTION OF THE EMBODIMENTS

While the disclosed invention is described herein according to its use with a vitreoretinal surgery system, those of ordinary skill in the understand will understand that the disclosed invention may be used with a variety of other equipment, both medical and non-medical, which require an operator to switch between flows of different fluids during an established procedure.

As shown in FIG. 1, prior art fluid flow systems used by vitreoretinal surgeons typically include a manually actuated stop cock valve 900 for changing fluids supplied to a patient's eye through an infusion cannula 904 during surgery. During normal operation the infusion line 902 is open and air line 906 is closed, thus allowing a controlled flow of surgical infusion solution to the infusion cannula 904. When the need arises to switch from the flow of surgical infusion solution to air, the position of the stop cock valve 900 is manually changed. As previously indicated, if the stop cock valve 900 is inadvertently moved to a position which blocks the flow of both surgical infusion solution and air, the eye being operated on may go soft thus adding further complications to what is already a delicate procedure.

According to the present invention, vitreoretinal surgeons will be provided with a new level of control of fluid flow during vitreoretinal surgery by being able to switch between fluids such as surgical infusion solution and air automatically. Such fluid flow from a source of surgical infusion solution or pressurized air may be changed by the use of an electrical switch on a footswitch or the input provided on a GUI (graphical user interface) control.

As shown in FIG. 2, a system 10 incorporating the present invention replaces the prior art manually operated stop cock valve 900 with an automatic stop cock valve or a back flow prevention valve 20 which is constructed and arranged to enable the vitreoretinal surgeon to switch between fluids such as surgical infusion solution and air or some other gas without the need to manually change the position of a prior art stop cock valve 900. By removing the need to manually change the position of a prior art stop cock valve 900, the surgeon's dependency on assistants, fellows, scrub nurses and/or scrub techs is reduced and the potential problem of an interrupted flow by the switching of a prior art manually operated stop cock valve 900 to a non-functional position is avoided.

As may be seen in FIG. 3, the preferred embodiment 300 of the automatic stop cock valve 20 of the present invention is enclosed within a tee-shaped fitting 302. The tee shaped fitting 302 is placed between the infusion line 902 and an air or gas flow line 906. When surgical infusion solution is flowing through the infusion line 902 to an infusion cannula 904, the surgical infusion solution flows through the straight portion 304 of the tee-shaped fitting 302. When the surgical infusion solution is de-activated and the source of air or gas is activated, the air flows through a stem portion 306 of the tee-shaped fitting 302 and opens a normally closed duck bill valve 320. The normally closed duck bill valve is held in place by a fitting 322 which is threadably 334 connected to the tee-shaped fitting 302. The two bill portions 323, 324 of the duck bill valve 320 will remain separated from one another as long as there is sufficient force from the flow of air through the stem portion 306 of the tee shaped fitting 302 to overcome the inherent bias in the beam strength of the two bill portions 323, 324 due to the elasticity of the rubber or flexible material from which the duck bill valve 320 is made. When the air pressure is no longer sufficient to keep the two bill portions 323, 324 separated from one another, the two bill portions 323, 324 will come together as shown in FIG. 3, thereby blocking the flow of fluid through the stem portion 306 of the fitting 302.

Accordingly, during normal infusion to the infusion cannula 904, as shown in FIG. 2, there is a controlled flow of surgical infusion solution. The air line 906 is closed. As shown in FIG. 3, the check valve 20, a duck bill valve 320 in the preferred embodiment 300, prevents any back flow of surgical infusion solution into the air line 906. When the vitreoretinal surgeon wants to switch from the infusion of surgical infusion solution to the infusion of air or some other gas, the surgeon activates an electrical switch or touches a GUI. The surgical infusion solution pressure is decreased to a pressure less than the air or gas pressure and/or the air or gas pressure is increased to a pressure greater than the surgical infusion solution pressure. This causes the flow of surgical infusion solution through the infusion line 902 to terminate and the flow of air or gas through line 906 to begin. The pressure of the air or gas opens the check valve 20 thereby allowing air to be infused into the eye through a third line 903 connected to the infusion cannula 904. If desired, the switching of fluid can be reversed thus allowing the vitreoretinal surgeon to switch from air or gas back to the fluid in the infusion line 902.

Those of ordinary skill in the art will understand that while a duckbill valve 320 has been shown in the preferred embodiment 300, other types of back flow prevention valves may be used without departing from the present invention.

In FIG. 4, a first alternate embodiment 400 of the system of the disclosed invention includes a normally closed flapper type valve assembly 420. As may be further seen in FIG. 4, the normally closed flapper type valve assembly 420 is located in the stem 406 portion of a tee shaped fitting 402. As in the previous embodiment 300 a fitting 422 is threadably 434 connected to the tee-shaped fitting 402. During the flow of surgical infusion solution, flow is through the straight portion 404 of the tee shaped fitting 402. When the flow of fluid through the infusion line 902 is caused to stop and the flow of air or gas begins, the force from the air or gas pressure overcomes the force keeping the flapper type valve assembly 420 closed and the flapper valve assembly 420 opens, thus permitting the flow of air through the stem portion 406 of the tee shaped fitting 420 out the exit portal 408 of the tee fitting shaped fitting 402 and into the infusion cannula 904.

In FIG. 5 is shown a second alternate embodiment 500. Herein an umbrella type valve assembly 520 is used. As in preferred embodiment 300 and the first alternate embodiment 400, a fitting 552 is threadably 534 attached to the tee-shaped fitting 502. Normal flow of fluid through the infusion line enters an entry portal 510 and continues through the straight portion 504 of the tee shaped fitting 502. When the flow of fluid through the infusion line 902 terminates and the flow of air or gas begins, the air or gas pressure causes the umbrella shaped valve assembly 520 to open. Those of ordinary skill in the art will see that the conical sides 522 of the normally closed umbrella type valve assembly 520 engage a seat 524. Air or gas pressure causes the conical sides 522 of the umbrella type valve assembly 520 to move away from the seat 524 thus opening a path for the flow of air through the stem portion 506 of the tee shaped fitting 502. Air or gas continues to flow past the umbrella type valve assembly 520 until the air pressure is no longer sufficient to keep the conical sides 522 of the umbrella type valve assembly 520 away from the seat 524, at which time the umbrella type valve assembly 520 returns to its normally closed position.

A ball type valve assembly 620 is used in the embodiment 600 shown in FIG. 6. As in the first alternate embodiment 400 and in the second alternate embodiment 500, fluid in the infusion line 902 enters the entry portal 610, flows through the straight portion 604 of the tee shaped fitting 602 and leaves via the exit portal 608. When the flow of air or gas is initiated the air pressure is sufficient to overcome the force of the spring portion 626 of the ball type valve assembly 620 thus causing the ball 622 to move away from the seat 624. The ball type valve assembly is held in place by a fitting 652 threadably 634 attached to the tee-shaped fitting 602. A flow path through the stem portion 606 of the tee shaped fitting 602 is now open for the passage of air through the exit portal 608 to the infusion cannula 904.

Those of ordinary skill in the art will understand that there are still a variety of different types of back flow prevention valves that may be used with the disclosed invention 10. For example, the spring 626 biased ball type valve assembly 620 shown in FIG. 6 maybe replaced with spring 726 biased poppet type valve assembly 720 in the alternate embodiment 700 illustrated in FIG. 7. The construction and operation of this embodiment 700 is similar to the operation of the embodiment 600 shown in FIG. 6 except that the poppet 722 has wide angled sides 723 which may contain an O-ring 725 for engagement with seat 724.

In the alternate embodiment 800 shown in FIG. 8, the tee-shaped housing 602 shown in FIG. 6 has been replaced with a Y-shaped housing 802. The use of a Y-shaped housing 802 in the place of the tee shaped housing shown in FIG. 6 does not affect the operation of the invention 10. Those of ordinary skill in the art will understand that other housings have a variety of shapes may be used without departing from the scope of the present invention.

In the alternate embodiment shown in FIG. 9, the Y-shaped housing 1002 of fitting 1000 does not include a back flow prevention valve. Instead, a valve assembly 1004 well known to those of ordinary skill in the art is operatively coupled to infusion line 902 for stopping or enabling the flow of surgical infusion fluid into fitting 1000, and a valve assembly 1006 well known to those of ordinary skill in the art is operatively coupled to air or gas flow line 906 for stopping or enabling the flow of air or gas into fitting 1000. Although not shown in FIG. 9, housing 1002 could employ a tee-shape or other shape. Valves 1004 and 1006 may be any manual, electrical, mechanical, or pneumatic valve for stopping or enabling the flow of a fluid through lines 902 and 906, respectively. Valve assemblies 1004 and 1006 are preferably manually, electrically, mechanically, or pneumatically actuated pinch valves.

While the present invention has been shown and described according to its preferred and alternate embodiments, those of ordinary skill in the art will understand that still other embodiments have been enabled by the foregoing disclosure. Such other embodiments shall be included within the scope and meaning of the appended claims. 

1. A flow control device for use in an ophthalmic surgical system for controlling the flow of fluid to an infusion cannula, said flow control device comprising: a first input port connected to a source of a first fluid; a second input port connected to a source of a second fluid; an exit port connected to the infusion cannula; a back flow prevention valve constructed and arranged to prevent the flow of said first fluid to said source of said second fluid.
 2. The flow control device as defined in claim 1 wherein said back flow prevention valve is a duck bill valve.
 3. The flow control device as defined in claim 1 wherein said back flow prevention valve is a flapper valve assembly.
 4. The flow control device as defined in claim 1 wherein said back flow prevention valve is an umbrella check valve assembly.
 5. The flow control device as defined in claim 1 wherein said back flow prevention valve is a ball check valve assembly.
 6. The flow control device as defined in claim 1 wherein said back flow prevention valve is a poppet valve assembly.
 7. A flow control system comprising: a source for the flow of a first fluid; a source for the flow of a second fluid; means for switching between the flow of said first fluid and the flow of said second fluid; an infusion line for the flow of said first fluid; a second line for the flow of said second fluid; a fitting constructed and arranged for insertion into said infusion line and said second line, said fitting including a first entry portal for said first fluid, and second entry portal for a second fluid and an exit portal for either said first fluid or said second fluid; a normally closed back flow prevention valve located in said second portal, said normally closed back flow prevention valve being openable by the flow of said second fluid when the flow of fluid is changed from said first fluid to said second fluid.
 8. The flow control system as defined in claim 7 wherein said normally closed back flow prevention valve is a duck bill valve.
 9. The flow control system as defined in claim 7 wherein said normally closed back flow prevention valve is a flapper valve assembly.
 10. The flow control system as defined in claim 7 wherein said normally closed back flow prevention valve is an umbrella valve assembly.
 11. The flow control system as defined in claim 7 wherein said normally closed back flow prevention valve is spring biased ball valve assembly.
 12. The flow control system as defined in claim 7 wherein said normally closed back flow prevention valve is a spring biased poppet valve assembly.
 13. The flow control system as defined in claim 7 further including a third line and an infusion cannula.
 14. A method for preventing back flow into the source of an alternate fluid when switching between the flow of a primary fluid and the flow of an alternate fluid, said method comprising the steps of: connecting a first entry portal of a fitting to enable the flow of the primary fluid to an exit portal of said fitting; connecting a second entry portal of said fitting to enable the flow of the alternate fluid to said exit portal of said fitting; inserting a normally closed back flow prevention valve into said second entry portal of said fitting to block the flow of said alternate fluid through said fitting until the force of the flow of said alternate fluid is sufficient to cause said normally closed back flow prevention valve to open.
 15. The method as defined in claim 13 wherein said normally closed back flow prevention valve prevents the back flow of the primary fluid into the flow of the alternate fluid.
 16. The method as defined in claim 13 wherein said normally closed back flow prevention valve is opened when the flow of the primary fluid is terminated and the flow of the alternate fluid is initiated.
 17. A flow control system comprising: an infusion line for the flow of a first fluid; means for stopping the flow of said first fluid; a second line for the flow of a second fluid; means for stopping the flow of said second fluid; a fitting constructed and arranged for insertion into said infusion line and said second line, said fitting including a first entry portal for said first fluid, and second entry portal for a second fluid and an exit portal for either said first fluid or said second fluid.
 18. The flow control system as defined in claim 17 wherein said means for stopping the flow of said first and second fluids are manually actuated valves.
 19. The flow control system as defined in claim 17 wherein said means for stopping the flow of said first and second fluids are electrically actuated valves.
 20. The flow control system as defined in claim 17 wherein said means for stopping the flow of said first and second fluids are mechanically actuated valves.
 21. The flow control system as defined in claim 17 wherein said means for stopping the flow of said first and second fluids are pneumatically actuated valves.
 22. The flow control system as defined in claim 17 wherein said means for stopping the flow of said first and second fluids are manually, electrically, mechanically, or pneumatically actuated pinch valves. 